Tread portion of an automobile tire



FIG. 1 is a perspective view of a tread portion of an automobile tire;

FIG. 2 is a front view thereof;

FIG. 3 is a left side view thereof; and,

FIG. 4 is a fragmentary enlarged view showing the details of the tread portion thereof.

Dashed lines in the figures show environmental structure only, and form no part of the claimed design. 

The ornamental design for a tread portion of an automobile tire, as shown and described. 